The Mass and the liturgy · Question 9
Do purple vestments, incense, and candles hold some special power?

The question: “If the liturgical color is wrong or a candle goes out, will something bad happen?”
The Church's answer: The liturgy uses visible signs — color, vesture, light, incense, space — to bring out what the faith means. The colors of the Roman liturgy help the eye recognize the character of the mystery being celebrated and the movement of the seasons. A candle can call to mind the light of Christ; incense, the honor given to God and prayer rising to him. Signs like these are a language that helps people with bodies and senses pray as a community.
But the objects themselves hold no power to foretell the future or to steer God. A sacrament does not become invalid on its own, and no disaster follows, because the wrong color was picked by mistake or the wind blew a candle out. A mistake against the liturgical norms should be noticed and put right, not inflated into superstition and fear. Beauty in the liturgy is likewise not a contest of expensive decoration; it has to serve noble simplicity and the true meaning of the signs.
If they press further: “So if there's no power in them, can we do the colors and the decoration any way we like?” — saying a thing has no magic in it is not saying it has no meaning. The signs the Church has appointed serve the memory and the unity of the community, so we prepare them as carefully as we can. At the same time, we don't judge a poor community as less holy for which expensive objects it has or hasn't got.
In one sentence: “Liturgical colors and candles and incense are signs that let the body recognize the faith; they aren't magical instruments. Use them with care, and don't turn a mistake into an evil omen.”